Triheptanoin for the treatment of glucose transport 1 deficiency

ABSTRACT

Provided are methods for treating GLUT1 and related brain energy deficiencies comprising administering odd-carbon fatty acid sources, e.g., C5 or C7 fatty acid sources, and related compositions.

BACKGROUND

Technical Field

Embodiments of the present invention relate to methods for treatingGLUT1 and related brain energy deficiencies comprising administeringodd-carbon fatty acid sources, e.g., C5 or C7 fatty acid sources, andrelated compositions.

Description of the Related Art

GLUT1 deficiency is a rare progressive neurogenetic disordercharacterized by encephalopathy with progressive intellectualdisability, drug-resistant epilepsy, motor disorders, and acquiredmicrocephaly.¹⁻⁴ The clinical spectrum of GLUT1 deficiency syndromeincludes developmental delay and movement disorders without epilepsy,⁴as well as familial and sporadic paroxysmal exercise-induced dyskinesiawith or without epilepsy.⁵ There are varying degrees of cognitiveimpairment with dysarthria, dysfluency, and expressive language deficitsthat are more severe than receptive language deficits. In most patients,the cerebrospinal fluid (CSF) to blood glucose ratio is below 0.50, andCSF lactate is low to normal.³ GLUT1 deficiency can be diagnosed bymutation analysis of the SLC2A1 gene, and deficient GLUT1 functionconfirmed by analysis of glucose uptake into erythrocytes.

Early diagnosis of GLUT1 deficiency is critical because it allows fortreatment with a ketogenic diet, a severely restricted diet consistingof 70-90% fat and very low carbohydrate diet that mimics the metabolicstate of fasting. Ketogenic diets generate ketone bodies as analternative energy source for the brain and can thereby reduce thefrequency of seizures and dystonic movements.^(6,7) Because ketonebodies are not affected by the GLUT1 defect (ketone bodies use anothertransporter to enter the central nervous system), they can supply analternative source of fuel to the brain, effectively correcting thebrain energy metabolism deficiency.⁷ However, ketogenic diets aredifficult to comply with long-term because of certain adverse sideeffects the extreme dietary choices require. Side effects of ketogenicdiets include constipation, low-grade acidosis, hypoglycemia,hyperlipidemia and hypercholesterolemia. Long-term ketogenic diets maycause retarded growth, bone fractures, and kidney stones.⁸

Accordingly, there remains a need in the art for treating GLUT1deficiencies and similar defects in brain energy metabolism.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention include methods of treating a GLUT1deficiency in a subject in need thereof, comprising administering to thesubject an odd-chain fatty acid source. In some embodiments, the subjecthas a disease-associated mutation in at least one SLC2A1 gene.

In certain embodiments, the subject has experienced one or more ofseizures, developmental delay, acquired microcephaly, spasticity,ataxia, or paroxysmal exertion-induced dyskinesia.

In particular embodiments, the subject has hypoglycorrhachia withouthypoglycemia. In specific embodiments, the hypoglycorrhachia ischaracterized by one or more of cerebrospinal fluid (CSF) glucose ofabout or less than about 2.2 mmol/L, CSF lactate of about or less thanabout 1.3 mmol/L, or a ratio of CSF/plasma glucose of about or less thanabout 0.4.

In some embodiments, the subject is diagnosed with decreased3-O-methyl-D-glucose uptake in erythrocytes. In certain embodiments, thesubject has cerebral fluoro-deoxy-glucose positron emission tomography(PET) findings characterized by diffuse hypometabolism of the cerebralcortex and regional hypometabolism of the cerebellum and thalamus.

In certain embodiments, the odd-chain fatty acid source is administeredas a unit dosage of about 2-150 grams. In certain embodiments, thesubject is an infant and the odd-chain fatty acid source is administeredas a unit dosage of about 1-6 grams/kg. In certain embodiments, thesubject is a young child, adolescent, or adult and the odd-chain fattyacid source is administered as a unit dosage of about 0.5-4 grams/kg. Incertain embodiments, the odd-chain fatty acid source provides at leastabout 30-35% of the total calories in the diet of the subject. Incertain embodiments, the odd-chain fatty acid source is administered atabout 1 to about 10 grams/kg/24 hours, about 1 to about 5 grams/kg/24hours, or about 1 to about 2 grams/kg/24 hours.

In some embodiments, the odd-chain fatty acid source is administeredthree times a day, twice a day, or once per day. In certain embodiments,the odd-chain fatty acid source is administered for one month, twomonths, six months, twelve months, or eighteen months.

In certain embodiments, the odd-chain fatty acid source is administeredin the absence of a ketogenic diet. In some embodiments, the odd-chainfatty acid is administered as part of a ketogenic diet.

Some methods comprise oral administration of the odd-chain fatty acid.In particular embodiments, the odd-chain fatty acid is formulated as anoil supplement. In specific embodiments, the odd-chain fatty acid isformulated as a gel capsule.

In certain embodiments, the odd-chain fatty acid is administered incombination with an anti-seizure medication.

In certain embodiments, the odd-chain fatty acid source comprisestriheptanoin or a derivative thereof. In specific embodiments, thetriheptanoin is ultrapure triheptanoin.

Also included are methods of determining a treatment regimen for asubject with GLUT1 deficiency, as described herein, comprising detectingthe level of one or more Krebs cycle intermediates in the subjecttreated for a GLUT1 deficiency, and determining a treatment regimenbased on an increase or decrease in the level of one or more Krebs cycleintermediates.

Also included are methods of monitoring treatment of a subject withGLUT1 deficiency, as described herein, comprising detecting the level ofone or more Krebs cycle intermediates or derivatives in the subjecttreated for a GLUT1 deficiency, wherein an increase or decrease in thelevel of one or more Krebs cycle intermediates or derivatives comparedto a predetermined standard level is predictive of the treatmentefficacy of the GLUT1 deficiency treatment.

Also included are methods of determining a treatment regimen for asubject with GLUT1 deficiency, as described herein, comprising detectingthe level of one or more ketone bodies in the subject treated for aGLUT1 deficiency and determining a treatment regimen based on anincrease or decrease in the level of one or more ketone bodies.

Also included are methods of monitoring treatment of a subject withGLUT1 deficiency, as described herein, comprising detecting the level ofone or more ketone bodies in the subject treated for a GLUT1 deficiency,wherein an increase or decrease in the level of one or more ketonebodies compared to a predetermined standard level is predictive of thetreatment efficacy of the GLUT1 deficiency treatment. In someembodiments, the ketone bodies are selected from 3-hydroxypentanoate and3-ketopentanoate.

In certain embodiments, the one or more Krebs cycle intermediates or theone or more ketone bodies are measured in a biological sample from asubject treated for a GLUT1 deficiency. In specific embodiments, thebiological sample is selected from blood, skin, hair follicles, saliva,oral mucous, vaginal mucous, sweat, tears, epithelial tissues, urine,semen, seminal fluid, seminal plasma, prostatic fluid, pre-ejaculatoryfluid (Cowper's fluid), excreta, biopsy, ascites, cerebrospinal fluid,lymph, brain, and tissue extract sample or biopsy sample.

In some embodiments, the one or more Krebs cycle intermediates or theone or more ketone bodies are measured by brain imaging. In someembodiments, the brain imaging is selected from computed axialtomography, diffuse optical imaging, event-related optical signal,magnetic resonance imaging, functional magnetic resonance imaging,magneto encephalography, positron emission tomography, and single-photonemission computed tomography.

Certain embodiments relate to methods of treating or preventing diseasesof the brain affecting energy metabolism in a subject, comprisingadministering to the subject an effective amount of triheptanoin, wherethe administration of triheptanoin restores mitochondrial energyfunction and net biosynthesis through anaplerosis.

Also included are odd-chain fatty acid sources (and relatedcompositions) for use in treating a GLUT1 deficiency and optionally aGLUT1 deficiency-associated condition or disorder. In certainembodiments, the odd-chain fatty acid source provides aclinically-effective or statistically significant therapeutic effect inthe treatment of the GLUT1 deficiency and/or the GLUT1deficiency-associated condition or disorder. In some embodiments, theGLUT1 deficiency-associated condition or disorder is seizures, e.g.,epileptic seizures. In specific embodiments, the odd-chain fatty acidsource is triheptanoin or a derivative thereof.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention relate to the use of anaplerotictherapies to treat brain energy deficiencies such as GLUT1 deficiencies.The anaplerotic therapies described herein include the administration ofodd-chain fatty acid sources such as triheptanoin. Odd-chain fatty acidsources supply odd-carbon ketone bodies to the brain (e.g.,3-hydroxypentanoate and 3-ketopentanoate)¹² and replenish substrates ofthe Krebs cycle, including both acetyl-CoA (to replenish energyproduction) and propionyl-CoA (to replenish Krebs cycle intermediatesand net biosynthesis)⁹. Ketogenic diets, the standard of care for suchdeficiencies, supply food-derived even-carbon ketones to the brain andthereby replenish acetyl-CoA for energy production, but do not supplythe odd-carbon ketones required to replenish propionyl-CoA and netbiosynthesis (e.g., for neurotransmitter synthesis). Hence, relative tostandard therapies for brain energy deficiencies, odd-chain fattyacid-based anaplerotic therapies provide the advantage of improving bothbrain energy production and net biosynthesis without the adverse sideeffects associated with ketogenic diets.

DEFINITIONS

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by those of ordinary skillin the art to which the invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, preferred methods andmaterials are described. All publications, patents, and patentapplications cited herein are incorporated by reference in theirentireties.

The articles “a” and “an” are used herein to refer to one or more thanone (i.e., to at least one) of the grammatical object of the article. Byway of example, “an element” means one element or more than one element.

By “about” is meant a quantity, level, value, number, frequency,percentage, dimension, size, amount, weight or length that varies by asmuch as 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1% to a referencequantity, level, value, number, frequency, percentage, dimension, size,amount, weight, length, or other unit described herein. In some aspects,the term “about” is used to indicate that a value includes the standarddeviation of error for the device or method being employed to determinethe value.

The terms “anaplerosis” and “anaplerotic” refer to reactions that formintermediates of one or more metabolic pathways. Examples includereactions that replenish tricarboxylic acid (TCA) cyclic intermediate(s)that have been extracted for biosynthesis, and thereby restore normalenergy metabolism. In some aspects, these terms refer to the formationof the TCA cycle intermediates acetyl-CoA and propionyl-CoA/succinylCoA, for example, by directly or indirectly providing C5-ketone bodiesthat are converted to acetyl-CoA and propionyl-CoA, the latter beingconverted to succinyl-CoA. In some instances, heptanoate can also beproduced by the liver and delivered to the brain to supply the metabolicneeds of glia and neurons (e.g., where the glia convert the heptanoateinto other energy intermediates to supply the adjacent neurons).Anaplerotic therapies are based on the existence of an energy deficit incertain tissues in part because of the lack of sufficient TCA cycleintermediates in mitochondria that are otherwise critical for theconversion of food into energy and biosynthetic intermediates.Anaplerotic therapies provide alternative substrates for the TCA cycleto restore its function and thereby enhance ATP production and netbiosynthesis in desired tissues, particularly those of the centralnervous system.^(9,10)

The terms “clinical-efficacy” and “clinically-effective” refer to atreatment that results in a statistically significant therapeuticeffect. By “statistically significant” it is meant that the result wasunlikely to have occurred by chance. Statistical significance can bedetermined by any method known in the art. Commonly used measures ofsignificance include the p-value, which is the frequency or probabilitywith which the observed event would occur, if the null hypothesis weretrue. If the obtained p-value is smaller than the significance level,then the null hypothesis is rejected. In simple cases, the significancelevel is defined at a p-value of 0.05 or less.

Thus, according to some embodiments, administering an odd-chain fattyacid source according to the methods of the present invention provides astatistically significant therapeutic effect in the treatment of brainenergy deficiency such as a GLUT1 deficiency and/or a GLUT1deficiency-associated condition or disorder (e.g., seizures such asepileptic seizures). In some embodiments, the statistically significanttherapeutic effect is determined based on one or more standards orcriteria provided by one or more regulatory agencies in the UnitedStates, e.g., FDA or other countries. In certain embodiments, thestatistically significant therapeutic effect is determined based onresults obtained from regulatory agency approved clinical trial set upand/or procedure.

In some embodiments, the statistically significant therapeutic effect isdetermined based on a patient population of at least 10, 20, 30, 40, 50,60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 or2000. In specific embodiments, the statistically significant therapeuticeffect is determined based on a patient population that is appropriatefor an orphan drug indication. In some embodiments, the statisticallysignificant therapeutic effect is determined based on data obtained fromrandomized and double-blinded clinical trial set-up. In someembodiments, the statistically significant therapeutic effect isdetermined based on data with a p-value of less than or equal to about0.05, 0.04, 0.03, 0.02 or 0.01. In some embodiments, the statisticallysignificant therapeutic effect is determined based on data with aconfidence interval greater than or equal to 95%, 96%, 97%, 98% or 99%.In some embodiments, the statistically significant therapeutic effect isdetermined on approval of Phase III clinical trial of the methodsprovided by the present invention, e.g., by FDA in the US.

In some embodiments, the clinically-effective or statisticallysignificant therapeutic effect is determined by a randomized doubleblind clinical trial of a patient population of at least 10, 20, 30, 40,50, 60, 70, 80, 90, 100, 200, 300 or 350, or a patient populationappropriate for an orphan drug indication, treated with an odd-chainfatty acid source optionally in the absence of a ketogenic diet. In someembodiments, the statistically significant therapeutic effect isdetermined by a randomized clinical trial of a patient population using,for example, occurrence of seizures (e.g., total number of seizures,number of seizures per unit/time), occurrence of dystonic (movements) orother neuurological events described herein, 6-minute walk test, or anycombination thereof or any other commonly accepted criteria or endpointsfor a GLUT1 deficiency or a GLUT1-associated disorder or condition.

In general, statistical analysis can include any suitable methodpermitted by a regulatory agency, e.g., FDA in the US or China or anyother country. In some embodiments, statistical analysis includesnon-stratified analysis, log-rank analysis, e.g., from Kaplan-Meier,Jacobson-Truax, Gulliken-Lord-Novick, Edwards-Nunnally, Hageman-Arrindeland Hierarchical Linear Modeling (HLM) and Cox regression analysis

The terms “Krebs cycle,” “citric acid cycle (CAC),” and “tricarboxylicacid (TCA) cycle” are used interchangeably to refer to the series ofchemical reactions used by aerobic organisms to generate energy throughthe oxidation of acetate (derived from carbohydrates, fats and proteins)into carbon dioxide and adenosine triphosphate (ATP).

The term “modulating” includes “increasing” or “enhancing,” as well as“decreasing” or “reducing,” typically in a statistically significant ora physiologically significant amount as compared to a control. An“increased” or “enhanced” amount is typically a “statisticallysignificant” amount, and may include an increase that is about 1.1, 1.2,1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6,2.7, 2.8, 2.9, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.3, 4.4, 4.6, 4.8, 5,6, 7, 8, 9, 10, 15, 20, 30, 40, 50 or more times (e.g., 100, 200, 500,1000 times) (including all integers and decimal points and ranges inbetween and above 1, e.g., 5.5, 5.6, 5.7. 5.8, etc.) the amount producedby a control (e.g., the absence or lesser amount of a compound, adifferent compound or treatment), or the amount of an earlier time-point(e.g., prior to treatment with a compound). A “decreased” or “reduced”amount is typically a “statistically significant” amount, and mayinclude a 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%,15%, 16%, 17%, 18%, 19%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%,65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100% decrease (including allintegers and decimal points and ranges in between) in the amount oractivity produced by a control (e.g., the absence or lesser amount of acompound, a different compound or treatment), or the amount of anearlier time-point (e.g., prior to treatment with a compound).

As used herein, the term “subject” includes a living mammalian organism,such as a human, monkey, cow, sheep, goat, dogs, cat, mouse, rat, guineapig, or transgenic species thereof. In certain embodiments, the subjectis a primate. Non-limiting examples of human subjects or patientsinclude adults, juveniles, infants, and fetuses.

“Substantially” or “essentially” includes nearly totally or completely,for instance, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or greater of somegiven quantity.

A “therapeutically effective amount” or “effective amount” includes anamount of an agent of the invention which, when administered to amammal, preferably a human, is sufficient to accomplish a desired orintended result. For example, an “effective amount” of an agent, e.g.,triheptanoin, administered to a subject for treatment means that amountwhich is sufficient to effect an improvement in a GLUT1 deficiencyand/or a reduction in one or more of its associated clinical pathologies(e.g., seizures). The amount of a compound of the invention whichconstitutes a “therapeutically effective amount” will vary depending onthe compound, the condition and its severity, the manner ofadministration, and the age of the mammal to be treated, but can bedetermined routinely by one of ordinary skill in the art having regardto his own knowledge and to this disclosure.

“Treatment” or “treating” includes (1) inhibiting a disease orcondition, such as GLUT1 deficiency and/or its associated conditions, ina subject experiencing or displaying the pathology or symptomatology ofthe disease or condition (e.g., reducing the pathology or symptomatologyreducing, further development of the pathology or symptomatology); (2)ameliorating a disease or condition, such as GLUT1 deficiency and/or itsassociated conditions, in a subject that is experiencing or displayingthe pathology or symptomatology of the disease or condition (e.g.,reversing the pathology and/or symptomatology); or (3) effecting anymeasurable decrease in a disease or condition, such as GLUT1 deficiencyand/or its associated conditions, in a subject that is experiencing ordisplaying the pathology or symptomatology of the disease or condition.For example, triheptanoin and other odd-carbon fatty acid sources cantreat symptoms of GLUT1 deficiency in one or more of the followingnon-limiting ways: increased brain energy levels, increased brainanaplerosis, increased levels of spinal fluid glucose (e.g., such thatthe cerebrospinal fluid to blood glucose ratio is about 0.50 or above),reduced developmental delay, minimized or reduced cognitive impairment,minimized or reduced occurrence of seizures, or minimized or reducedoccurrence of dystonic movements. Also included are reduceddevelopmental abnormalities (such as decreased cognitive function,decreased rate of development and acquisition of new behaviors,difficulty with language or other complex neurologic skills) and reducedmovement disorders (e.g., ataxia, chorea, tremors, dysarthria, ormyoclonus).

“Prevention” or “preventing” includes: (1) inhibiting the onset of adisease or condition, such as GLUT1 deficiency, in a subject who may beat risk or predisposed to the disease or condition but does not yetexperience or display any or all of the pathology or symptomatology ofthe disease or condition; or (2) slowing or reducing the onset of thepathology or symptomatology of a disease or condition, such as a GLUT1deficiency, in a subject which may be at risk or predisposed to thedisease or condition but does not yet experience or display any or allof the pathology or symptomatology of the disease or condition.Non-limiting examples of symptoms of GLUT1 deficiencies are providedherein.

The term “triheptanoin” refers to a triglyceride of one, two, or three7-carbon straight chain saturated fatty acids. Triheptanoin isconsidered an anaplerotic compound. The term “tripentanoin” refers to atriglyceride of one, two, or three 5-carbon straight-chain saturatedfatty acids. Odd-carbon fatty acid sources including triheptanoin andtripentanoin can work similarly in allowing both the production ofacetyl-CoA to supply the TCA cycle and also the propionyl-CoA that getsconverted to succinyl-CoA in the anaplerotic process. Other examplesodd-chain fatty acid sources (e.g., triglycerides, diglycerides, freefatty acids) are described herein.

Methods of Treatment

Embodiments of the present invention relate to methods of treating brainenergy deficiencies (i.e., diseases of the brain affecting energymetabolism) in a subject in need thereof, comprising administering tothe subject an odd-chain fatty acid source. Such brain energydeficiencies typically lead to brain dysfunction because of theinadequate production of energy and net biosynthesis intermediatesrequired by glial cells and neurons. Ideally, the odd-chain fatty acidsource restores mitochondrial function through anaplerosis, for example,by increasing the availability of acetyl-CoA andpropionyl-CoA/succinyl-CoA in central nervous system tissues such asglial cells and neurons. Examples of brain energy deficiencies includebut are not limited to GLUT1 deficiencies, epilepsy, epilepsy-likedisorders, seizure disorders, ictal disorders, postictal disorders,interictal disorders, and paroxysmal brain dysfunctions.

In particular embodiments, the disease is a Glucose transporter 1(GLUT1) deficiency or a symptom or condition associated with a GLUT1deficiency. GLUT1 deficiencies include, for example, De Vivo disease,GLUT1 deficiency syndrome (GLUT1DS or G1D), and glucose transporterprotein syndrome (GTPS). GLUT1 facilitates the transport of glucoseacross the plasma membrane of mammalian cells. It is also referred to assolute carrier family 2-facilitated glucose transporter member 1(SLC2A1). GLUT1 deficiencies are typically caused by mutations or otherdefects in the GLUT1 gene, which result in decreased glucose transportacross the blood-brain barrier. In certain instances, the subject has orhas been diagnosed as having one or more disease-associated mutations inthe GLUT1 gene (the SLC2A1 gene). Most patients carry heterozygous denovo mutations in the GLUT1-gene but autosomal dominant and recessivetransmission have also been identified (see Verrotti et al., Eur J.Paedeatr. Neurol. 16:3-9, 2012).

GLUT1 and related deficiencies can be characterized, for example, byhypoglycorrhachia optionally without hypoglycemia. In some instances,hypoglycorrhachia is characterized by low cerebrospinal fluid (CSF)glucose, (<2.2 mmol/L), low CSF lactate, and/or a lowered CSF/plasmaglucose ratio (<0.4). This decrease in glucose transport/levels leads tobrain energy deficiencies in which the glia are unable to use glucose orto supply lactate to neurons. Accordingly, in certain aspects, thesubject has a low level of glucose in CSF, low levels of lactate in CSF,and/or a lowered CSF/plasma glucose ratio. For instance, in some aspectsthe subject has CSF glucose of about or less than about 2.2, 2.1, 2.0,1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, or0.5 mmol/L (e.g., prior to effective treatment). In some aspects thesubject has CSF lactate of about or less than about 1.3, 1.2 1.1, 1.0,0.9, 0.8, 0.7, 0.6, or 0.5 mmol/L (e.g., prior to effective treatment).In certain aspects the subject has a ratio of CSF/plasma glucose ofabout or less than about 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, or 0.1 (e.g.,prior to effective treatment).

In some instances, the subject is diagnosed with decreased3-O-methyl-D-glucose uptake in erythrocytes. Optionally, the subject hascerebral fluoro-deoxy-glucose positron emission tomography (PET)findings characterized by diffuse hypometabolism of the cerebral cortexand regional hypometabolism of the cerebellum and thalamus.

GLUT1 deficiencies associate with conditions such as inadequate brainfunction, seizures, motor disturbances, cognitive impairment,developmental delay, acquired microcephaly, spasticity, ataxia,paroxysmal exertion-induced dyskinesia, and other clinicalmanifestations. Thus, in certain embodiments the subject has a GLUT1deficiency and a GLUT1 deficiency-associated condition or disorder, andthe methods comprise treating the GLUT1 deficiency, the GLUT1deficiency-associated condition/disorder, or both. In specificembodiments, the GLUT1 deficiency-associated condition/disorder includesseizures and the subject has had or is at risk for having seizures.Seizures are episodes of disturbed brain function that cause changes inattention or behavior. They are caused by abnormally excited electricalsignals in the brain. In particular embodiments, the subject has had oris at risk for having epileptic seizures. By “epilepsy” (also calledepileptic seizure disorder) is meant is a chronic brain disordercharacterized by recurrent, unprovoked seizures. The seizures are causedby sudden, usually brief, excessive electrical discharges in neurons.Epileptic attacks can lead to loss of awareness, loss of consciousnessand/or disturbances of movement, autonomic function, sensation(including vision, hearing and taste), mood and/or mental function.Types of seizures include simple partial, complex partial andgeneralized seizures, such as tonic, clonic, tonic-clonic, absence,Status epilepticus, atonic and myoclonic seizures. The methods of thepresent invention are particularly suited to treatment ofmedically-refractory epilepsy, chronic epilepsy, acute epilepsy or drugresistant epilepsy. In particular embodiments, the subject has had aboutor at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more priorseizures, e.g., epileptic seizures. In certain embodiments,administration of the odd-chain fatty acid source reduces the frequencyor occurrence of seizures in the subject by about or at least about 10,20, 30, 40, 50, 60, 70, 80, 90, 100% over a defined period of time, forinstance, over 1, 2, 3, 4, 5, 6, 7, 8 weeks or more, over 1, 2, 3, 4, 5,6, 7, 8, 9, 10, 11, 12 months or more, or over 1, 2, 3, 4, 5, 6, 7, 8,9, 10 years or more.

Anaplerotic therapy using odd-chain fatty acid sources such as odd-chaintriglycerides (e.g., triheptanoin, a 7-carbon triglyceride) can be usedto replenish one or more substrates of the TCA cycle and thereby correctthe energy and net biosynthesis deficits in a GLUT1 deficiency. In someaspects, anaplerotic therapy halts or reverses the disease progressionand clinical neurological symptoms in patients with GLUT1 deficiency.

The terms “odd-chain” fatty acids and “odd-carbon” fatty acids are usedinterchangeably to refer to fatty acids (carboxylic acids with analiphatic tail) that consist of an odd number of carbon atoms. The fattyacids can be saturated or unsaturated. Examples of odd-chain fatty acidsinclude propionic acid, pentanoic acid, heptanoic acid, nonanoic acidand undecanoic acid. An odd-chain fatty acid “source” refers to amolecule or composition that comprises at least one odd-chain fattyacid. Examples include odd-chain free fatty acids, triglyceridescontaining at least one odd-chain fatty acid, diglycerides containing atleast one odd-chain fatty acid, monoglycerides containing an odd-chainfatty acid, and phospholipids containing at least one odd-chain fattyacid, including combinations/mixtures thereof. Also included arederivatives of any of the odd-chain fatty acid-containing moleculesdescribed herein.

As noted above, particular examples of odd-chain fatty acid sourcesinclude odd-chain fatty acid triglycerides (e.g., triheptanoin,tripentanoin), odd-chain fatty acid diglycerides, and odd-chain fattyacid monoglycerides. Thus, in some embodiments, the treatment of a GLUT1deficiency comprises administration of an effective amount of atriglyceride that comprises at least one odd-chain fatty acid, at leasttwo odd-chain fatty acids, or three odd-chain fatty acids. In someembodiments, the treatment of a GLUT1 deficiency comprisesadministration of an effective amount of a diglyceride that comprises atleast one odd-chain fatty acid or at least two odd-chain fatty acids. Insome embodiments, the treatment of a GLUT1 deficiency comprisesadministration of an effective amount of a monoglyceride that comprisesan odd-chain fatty acid. The odd-chain triglyceride or diglyceride ormonoglyceride can contain short, medium, and/or long odd-chainfatty-acids.

In some embodiments, the odd-chain triglyceride includes 5-carbontriglycerides, 7-carbon triglycerides, 9-carbon triglycerides, and/or15-carbon triglycerides. In certain embodiments, the odd-chaindiglyceride includes 5-carbon diglycerides, 7-carbon diglycerides,9-carbon diglycerides, and/or 15-carbon diglycerides. In particularembodiments, the odd-chain monoglyceride includes 5-carbonmonoglycerides, 7-carbon monoglycerides, 9-carbon triglycerides, and/or15-carbon monoglycerides. Some methods employ triglycerides,diglycerides, and/or monoglycerides of C5 fatty acids, triglycerides ofC7 fatty acids, and/or triglycerides of C9 fatty acids. Combinations oftriglycerides, diglycerides, and/or monoglycerides can also be employed.Specific examples include mixtures of 7-carbon triglycerides and5-carbon triglycerides. Also included are derivatives of the odd-chaintriglycerides described herein.

In certain embodiments, the odd-chain fatty acid source comprises orconsists of triheptanoin (glyceryl triheptanoate) or tripentanoin. Alsoincluded are salts, prodrugs, analogues, derivatives, substituted,unsaturated, branched forms, and derivatives thereof. Triheptanoin is atriglyceride made by the esterification of three n-heptanoic acidmolecules and glycerol and can be obtained by the esterification ofheptanoic acid and glycerol by any means known in the art. Triheptanoinis also commercially available through Sasol (Witten, Germany) asSpecial Oil 107, although without limitation thereto. Heptanoic acid isfound in various fusel oils in appreciable amounts and can be extractedby any means known in the art. It can also be synthesized by oxidationof heptaldehyde with potassium permanganate in dilute sulfuric, acid.Heptanoic acid is also commercially available through Sigma Chemical Co.(St. Louis, Mo.). In some embodiments, the triheptanoin is ultrapuretriheptanoin, as described in U.S. provisional application 61/709,080(incorporated by reference in its entirety). There are no toxic sideeffects reported with the long-term use of triheptanoin in humans.

Triheptanoin is metabolized in the liver to generate C5-ketone bodiesand heptanoate as sources of energy for the brain but without the needto induce generalized ketosis (e.g., via a strict diet), and thusexhibits significantly greater safety than other methods of treatingGLUT1 deficiencies. In addition, since ketone body formation is suppliedfrom medium chain fatty acids that do not suppress ketone body formationin the liver, the use of triheptanoin only requires approximately 25-35%fat calories from triheptanoin which can include carbohydrates, ratherthan the 70-90% calories from fat devoid of carbohydrates required for atraditional ketogenic diet.

After enteral absorption of triheptanoin, most of the heptanoatereaching the liver is β-oxidized into 1× anaplerotic propionyl-CoA and2× acetyl-CoA.⁹ The excess acetyl-CoA and propionyl-CoA are channeled toproduce C4- and C5-ketone bodies, which are exported from the liver toperipheral tissues.^(9,10) The production of these ketone bodies fromdietary triheptanoin occurs even when a meal contains carbohydrates.This results because the oxidation of heptanoate (a medium chain fattyacid) in liver mitochondria is not regulated by the carnitinepalmitoyltransferase system, the activity of which is otherwiseinhibited by dietary carbohydrates.⁹ However, to optimize itsanaplerotic effects, triheptanoin should represent at least 30 to 35% ofthe total calories.¹¹ Otherwise, glucose would be the main source ofenergy supply and the oxidation of triheptanoin could be reduced. TheC5-ketone bodies (3-hydroxypentanoate and 3-ketopentanoate) cross theblood-brain barrier and generate anaplerotic propionyl- and acetyl-CoAfor the Krebs cycle in brain tissues.¹² In addition to the C5-ketonebodies, the release of heptanoate occurs after administration (e.g.,ingestion) of triheptanoin. Heptanoate can cross the blood brain barrierand be metabolized in the glia to generate energy metabolites for theneurons. Given its odd-chain length, it can also create anapleroticintermediates and restore TCA cycle function in the brain.

In some embodiments, the odd-chain fatty acid source is administeredinstead of or in the absence of a ketogenic diet (or a substantiallyketogenic diet). That is, in some instances, the subject is not on aketogenic diet or as has failed to follow a ketogenic diet. Failure tofollow a ketogenic diet can include instances where the subject isunable to maintain the strict food choices or is medically unable tostay on a ketogenic diet because of side effects or issues with othermedications and/or disorders. By “absence of a ketogenic diet” is meanta dietary intake which does not have a higher than normal fat contentcompared to carbohydrate and protein. In some embodiments, an “absenceof a ketogenic diet” is a diet is which the ratio by weight of fat tocombined protein and carbohydrate is less than 3:1, and may be 2:1, 1:1,0.5:1 or a ratio where the fat content is even lower, or where fat isabsent.

In any of the treatment methods described herein, the combination ofC5-ketone bodies, heptanoate, and/or the intermediary metabolism of thebrain in glia or neurons may be involved in replacing the energydeficiency state that leads to defects in brain energy metabolism,including GLUT1-deficiency and its associated symptoms/pathologies.

Certain embodiments therefore include the use of odd-chain fatty acidsources (e.g., triheptanoin and related compositions) as dieterysupplements or neutraceuticals, for example, to improve or support brainenergy, improve or support brain metabolism, improve or support improvebrain function, or improve or support nervous system (e.g., CNS) energy,metabolism or function.

Administration and Dosages

Administration of the odd-chain fatty acid sources in pure form or in anappropriate pharmaceutical composition can be carried out via any of theaccepted modes of administration of agents for serving similarutilities. Typical routes of administering an odd-chain fatty acidsource or a composition comprising the same include, without limitation,oral, topical, transdermal, inhalation, parenteral, sublingual, buccal,rectal, vaginal, and intranasal routes. The term parenteral as usedherein includes subcutaneous injections, intravenous, intramuscular,intrasternal injection or infusion techniques. In specific embodiments,the odd-chain fatty acid source is administered or ingested orally.

An odd-chain fatty acid source or related composition may be in the formof a solid or liquid. In one aspect, the carrier(s) are particulate, sothat the compositions are, for example, in tablet or powder form. Thecarrier(s) may be liquid, with the compositions being, for example, anoral oil, an oral syrup, or an injectable liquid. In specificembodiments, the composition is a oil supplement of triheptanoin or aderivative thereof.

When intended for oral administration, the pharmaceutical composition ispreferably in either solid (e.g., powder) or liquid form, wheresemi-solid, semi-liquid, suspension, and gel forms are included withinthe forms considered herein as either solid or liquid.

As a solid composition for oral administration, the pharmaceuticalcomposition may be formulated into a powder, granule, compressed tablet,pill, capsule, chewing gum, wafer or the like form. Such a solidcomposition will typically contain one or more inert diluents or ediblecarriers. In addition, one or more of the following may be present:binders such as carboxymethylcellulose, ethyl cellulose,microcrystalline cellulose, gum tragacanth or gelatin; excipients suchas starch, lactose or dextrins, disintegrating agents such as alginicacid, sodium alginate, Primogel, corn starch and the like; lubricantssuch as magnesium stearate or Sterotex; glidants such as colloidalsilicon dioxide; sweetening agents such as sucrose or saccharin; aflavoring agent such as peppermint, methyl salicylate or orangeflavoring; and a coloring agent. When the pharmaceutical composition isin the form of a capsule, for example, a gelatin capsule, it maycontain, in addition to materials of the above type, a liquid carriersuch as polyethylene glycol or oil.

The pharmaceutical composition may be in the form of a liquid, forexample, an oil, elixir, syrup, solution, emulsion, or suspension. Theliquid may be for oral administration or for delivery by injection. Whenintended for oral administration, a composition may contain, in additionto the odd-chain fatty acid(s), one or more of sweetening agents,preservatives, dye/colorants and flavor enhancers. In a compositionintended to be administered by injection, one or more of a surfactant,preservative, wetting agent, dispersing agent, suspending agent, buffer,stabilizer and isotonic agent may be included.

The liquid pharmaceutical compositions of the invention, whether they besolutions, suspensions or other like form, may include one or more ofthe following adjuvants: sterile diluents such as water for injection,saline solution, preferably physiological saline, Ringer's solution,isotonic sodium chloride, fixed oils such as synthetic mono ordiglycerides which may serve as the solvent or suspending medium,polyethylene glycols, glycerin, propylene glycol or other solvents;antibacterial agents such as benzyl alcohol or methyl paraben;antioxidants such as ascorbic acid or sodium bisulfite; chelating agentssuch as ethylenediaminetetraacetic acid; buffers such as acetates,citrates or phosphates and agents for the adjustment of tonicity such assodium chloride or dextrose.

Certain compositions may be intended for rectal administration, in theform, for example, of a suppository, which will melt in the rectum andrelease the odd-chain fatty acid source. The composition for rectaladministration may contain an oleaginous base as a suitablenon-irritating excipient. Such bases include, without limitation,lanolin, cocoa butter and polyethylene glycol.

Odd-chain fatty acid sources and related compositions are formulated soas to allow the active ingredients contained therein to be bioavailableupon administration of the composition to a subject. Compositions thatwill be administered to a subject or patient usually take the form ofone or more dosage units, where for example, a tablet or capsule (e.g.,gel capsule) may be a single dosage unit, and a container may hold aplurality of dosage units. Actual methods of preparing such dosage formsare known, or will be apparent, to those skilled in this art; forexample, see Remington: The Science and Practice of Pharmacy, 20thEdition (Philadelphia College of Pharmacy and Science, 2000). In certainaspects, the composition to be administered contains a therapeuticallyeffective amount of an odd-chain fatty acid source, for treatment of adisease or condition of interest.

In some embodiments, a unit dosage comprises about or at least about 2 gto about 150 g, or about 2 g, 3 g, 4 g, 5 g, 10 g, 15 g, 20 g, 25 g, 30g, 35 g, 40 g, 45 g, 50 g, 55 g, 60 g, 65 g, 70 g, 75 g, 80 g, 90 g, 95g, 100 g, 125 g or 150 g, or more of an odd-chain fatty acid source(e.g., triheptanoin).

The frequency of administration of the compositions described herein mayvary from once-a-day (QD) to twice-a-day (BID) or thrice-a-day (TID),etc., the precise frequency of administration varying with, for example,the patient's condition, the dosage, etc

Table 1 below provides energy conversion values useful for calculatingdosages suitable for methods provided herein. Additional information canalso be found in Gidding et al. (Dietary Recommendations for Childrenand Adolescents: A Guide for Practitioners, Pediatrics, 117:544-559(2006); incorporated herein by reference in its entirety).

TABLE 1 Energy Conversion Values Table 1: Energy Conversion ValuesEnergy Density kJ/g kCal/g Fat 37 9 Ethanol (drinking alcohol) 29 7Proteins 17 4 Carbohydrates 17 4 Organic acids 13 3 Polyols (sugaralcohols, sweeteners) 10 2.4 Fiber 8 2

In certain embodiments a dosage is calculated by the weight of thesubject. According to the World Health Organization (WHO), boys frombirth to 5 years of age range in mass from approximately 2 kg to 30 kg.Boys of 5 years to 10 years of age range in mass from approximately 10kg to 50 kg. Girls from birth to 5 years of age range in mass fromapproximately 2 kg to 30 kg. Girls of 5 years to 10 years of age rangein mass from approximately 10 kg to 52 kg. See, for example, the WHOGrowth Standards, hereby incorporated by reference.

In certain embodiments, the dosage of the odd-chain fatty acid source,e.g., C7 carbon source such as triheptanoin, is from about 2-4 grams/kgfor infants, 1-2 grams/kg for young children (e.g., prepubescent orpubescent), or about 1 gram/kg for adolescents (e.g., post-pubescent)and adults. In specific embodiments, the dosage ranges from about 1-6,1-2, 2-3, 3-4, 4-5, or 5-6 grams/kg for infants, 0.5-4, 0.5-1, 1-1.5,1.5-2, 2-2.5, 2.5-3, 3-3.5, or 3.5-4 grams/kg for young children, orabout 0.5-4, 0.5-1, 1-1.5, 1.5-2, 2-2.5, 2.5-3, 3-3.5, or 3.5-4 grams/kgfor adolescents and adults.

In some embodiments, the unit dosage is the desired daily dosage (e.g.,grams/kg) multiplied by the average weight of the subject group, andoptionally divided by times per day for administration. For example, insome embodiments, the unit dosage for infants is 2-4 grams/kg multipliedby an average infant's weight, and optionally divided by one, two,three, four, five or six for daily administration. In particularembodiments, the unit dosage for young children through school age is1-2 grams/kg multiplied by an average young child's weight, andoptionally divided by one, two, three, four, five or six for dailyadministrations. In some embodiments, the unit dosage for adolescentsand adults is about 1 grams/kg multiplied by an average adolescent's oradult's weight, and optionally divided by one, two, three, or four fordaily administration. In some embodiments the unit dosage volume is inmilliliters or liters.

In some embodiments, the odd-chain fatty acid source (e.g.,triheptanoin) is provided in solution and/or oil from between about 0.25g/mL (i.e., 0.25 g per cc) to about 2 g/mL (i.e., 0.25 g per cc). Incertain embodiments, the odd-chain fatty acid source (e.g.,triheptanoin) is provided (e.g., in solution and/or oil) at about 0.25g/mL, 0.5 g/mL, 0.75 g/mL, 1 g/mL, 1.25 g/mL, 1.5 g/mL, 1.75 g/ml or 2g/mL.

In some embodiments, the odd-chain fatty acid source (e.g.,triheptanoin) is administered at about 1 to about 10 grams/kg/24 hours,about 1 to about 5 grams/kg/24 hours or about 1 to about 2 grams/kg/24hours. In some embodiments, the odd-chain fatty acid source (e.g.,triheptanoin) is administered at about 2-4 grams/kg/24 hours forinfants. In some embodiments, the odd-chain fatty acid source (e.g.,triheptanoin) is administered at about 2, 3 or 4 grams/kg/24 hours forinfants. In certain embodiments, the odd-chain fatty acid source (e.g.,triheptanoin) is administered at about 1-2 grams/kg/24 hours forchildren through school age. In some embodiments, the odd-chain fattyacid source (e.g., triheptanoin) is administered at about 1 or 2grams/kg/24 hours for children through school age. In some embodimentsthe odd-chain fatty acid source (e.g., triheptanoin) is administered atabout 1 gram/kg/24 hours for adolescents and adults.

Based on the suitable dosage, the odd-chain fatty acid source (e.g.,triheptanoin) can be provided in various suitable unit dosages. Forexample, an odd-chain fatty acid source can comprise a unit dosage foradministration one or multiple times per day, for 1-7 days per week.Such unit dosages can be provided as a set for daily, weekly and/ormonthly administration.

In some embodiments, the odd-chain fatty acid source (e.g.,triheptanoin) is administered about six times a day, about five times aday, about four times a day, about three times a day, about twice a day,or about once per day.

In certain embodiments, the daily dosage is divided into 1 to 6 dailydosages, 1 to 5 daily dosages, or 1 to 4 daily dosages. In someembodiments, the daily dosage is divided into 1 to 4 daily doses, 1 to 5daily doses, or 1 to 6 daily doses of 2, 5, 10, 15, 20, 25, 30, 35, 40or 50 cc. In some embodiments, the daily dosage is divided into 4 dailydoses of 15 cc to 20 cc for an adult. In specific embodiments, theodd-chain fatty acid source (e.g., triheptanoin) is provided in 1 g/mLand the daily dosage of 1 g/kg/day is divided into 4 daily dosages.

In some embodiments, the odd-chain fatty acid source (e.g.,triheptanoin) is administered for one week, two weeks, one month, twomonths, six months, twelve months or eighteen months.

In some embodiments, the odd-chain fatty acid source (e.g.,triheptanoin) is administered as part of a dosing regimen so as tomaintain a constant level of the odd-chain fatty acid source in thesubject. In some embodiments, the odd-chain fatty acid source can beadministered multiple times per day so as to maintain a constant levelin the blood.

In some embodiments, the dosage of the odd-chain fatty acid source(e.g., triheptanoin) provides at least about 10% to about 50%, at leastabout 20% to about 40%, at least about 25% to about 35%, or at leastabout 30% to about 35% of the total calories in the diet of saidsubject. In some embodiments, the odd-chain fatty acid source providesat least about 25-35% of the calories in the diet of infants and/oryoung children.

Odd-chain fatty acid sources may also be administered simultaneouslywith, prior to, or after administration of one or more other therapeuticor biologically active agents, dietary supplements, or any combinationthereof. Such combination therapies include administration of a singlepharmaceutical dosage formulation which contains an odd-chain fatty acidsource and one or more additional active agents, as well asadministration of the odd-chain fatty acid source and each active agentin its own separate pharmaceutical dosage formulation. For example, anodd-chain fatty acid source and the other active agent can beadministered to the patient together in a single oral dosage formulationsuch as a tablet, capsule (e.g., gel capsule), syrup, or oil, or eachagent administered in separate oral dosage formulations. Where separatedosage formulations are used, the odd-chain fatty acid source and one ormore additional active agents can be administered at essentially thesame time, i.e., concurrently, or at separately staggered times, i.e.,sequentially. Combination therapy is understood to include all theseregimens.

In some embodiments, the odd-chain fatty acid source (e.g.,triheptanoin) is administered in combination with a ketogenic diet, apartial ketogenic diet, or a C4 ketogenic diet. By “ketogenic diet” ismeant a high fat and low carbohydrate and protein diet. Typically, aketogenic diet contains a 3:1 to 4:1 ratio by weight of fat to combinedprotein and carbohydrate. A ketogenic diet may refer to a classicalketogenic diet comprising predominantly natural fats (inclusive ofnormal dietary fats and suitably long-chain triglycerides) or aketogenic diet comprising predominantly medium chain triglycerides andsuitably, even medium chain triglycerides. By “C4 ketogenic diet” ismeant a high fat and low carbohydrate and protein diet. Typically, a C4ketogenic diet contains a 3:1 to 4:1 ratio by weight of even chain fatto combined protein and carbohydrate. A C4 ketogenic diet increases theC4 ketones, β-hydroxybutyrate and acetoacetate, but not C5 ketones. A C4ketogenic diet may refer to a classical ketogenic diet comprisingpredominantly natural fats (inclusive of normal dietary fats andsuitably long-chain triglycerides) or a ketogenic diet comprisingpredominantly medium chain triglycerides and suitably, even medium chaintriglycerides, mostly C8 and C10 oil(s). In these and relatedembodiments, the odd-chain fatty acid source can be substituted forabout 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%,70%, 75%, 80%, 85%, 90% or 95% of the calories or amount of the fatportion of the full or partial ketogenic diet.

In some embodiments, the odd-chain fatty acid source (e.g.,triheptanoin) is combined with or administered in combination with afood entity. Food entities include for example yogurt, sauces, shakes,or any other food with which the odd-chain fatty acid source can becombined. In some embodiments, the odd-chain fatty acid source iscombined with an emulsifying component. In some embodiments, the foodcomponent comprises an emulsifying component.

In some embodiments, odd-chain fatty acid source (e.g., triheptanoin) isadministered in combination with an anti-seizure drug. Also included arepharmaceutical compositions that comprise an odd-chain fatty acid sourceand an anti-seizure drug. Examples of anti-seizure drugs include but arenot limited to Acetazolamide, Banzel, Barbexaclone, Beclamide,Brivaracetam, Carbamate, carbamazepine (Tegretol), Carbatrol,Carboxamide, Cerebyx, Clobazam, clonazepam (Klonopin), Clorazepate,Depakene, Depakote, Depakote ER, Depakote Sprinkles, Diamox, DiamoxSequels, Diastat, Diazepam, Dilantin, Epitol, Eslicarbazepine acetate,Ethadione, Ethosuximide, Ethotoin, Ezogabine, Felbamate, Felbatol,Fosphenytoin, Frisium, Fycompa, gabapentin (Neurontin), Gabitril,Inovelon, Keppra, Keppra XR, Klonopin, lacosamide (Vimpat), Lamictal,lamotrigine (Lamictal), lamotrigine (Lamictal), lamotrigine (Lamictal),levetiracetam (Keppra), Lorazepam, Luminal, Lyrica, M phenytoin,Mesuximide, Methazolamide, Methylphenobarbital, Midazolam, Mysoline,Neurontin, nimetazepam, Onfi, Oxcarbazepine, oxcarbazepine (Trileptal),Paraldehyde, Paramethadione, Perampanel, Phenacemide, Pheneturide,Phenobarbital, Phensuximide, Phenytek, phenytoin (Dilantin), PhenytoinSodium, Potassium bromide, Potiga, pregabalin (Lyrica), Primidone,rufinamide (Banzel), Sabril, Seletracetam, Stiripentol, Sultiame,Tegretol, Tegretol XR, temazepam, Tiagabine, topiramate (Topamax),Trileptal, Trileptal, Trileptal, Trimethadione, Trimethadione,Trimethadione, valproic acid (Depakote), Valpromide, Valnoctamide,vigabatrin (Sabril), vigabatrin (Sabril), Vimpat, Zarontin, orzonisamide (Zonegran). In certain of these and related embodiments, thesubject has a GLUT1 deficiency and is at risk for having seizures, orhas had at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more priorseizures. In certain embodiments, administration of the odd-chain fattyacid source in combination with the anti-seizure drug reduces thefrequency or occurrence of seizures in the subject by about or at leastabout 10, 20, 30, 40, 50, 60, 70, 80, 90, 100% over a defined period oftime, for instance, over 1, 2, 3, 4, 5, 6, 7, 8 weeks or more, over 1,2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 months or more, or over 1, 2, 3, 4,5, 6, 7, 8, 9, 10 years or more.

Monitoring Treatment

Certain embodiments include methods for monitoring and/or predicting thetreatment efficacy of a GLUT1 deficiency treatment as described herein.Such methods include detecting the level of one or more Krebs cycleintermediates or their derivatives in a subject (or in a biologicalsample from the subject) treated for a GLUT1 deficiency, wherein anincrease or decrease in the level of one or more Krebs cycleintermediates or their derivatives compared to a predetermined standardlevel indicates or is predictive of the treatment efficacy of the GLUT1deficiency treatment.

Also included are methods for determining the treatment regimen fortreating a GLUT1 deficiency as described herein. Such methods includedetecting the level of one or more Krebs cycle intermediates or theirderivatives in a subject (or in a biological sample from the subject)treated for a GLUT1 deficiency and determining a treatment regimen basedon an increase or decrease in the level of the one or more Krebs cycleintermediates.

Examples of Krebs cycle intermediates include acetyl-CoA, propionyl-CoA,and succinyl-CoA, including precursors and derivatives thereof.

Some embodiments include methods for monitoring and/or predicting thetreatment efficacy of a GLUT1 deficiency treatment as described herein,comprising detecting the level of one or more ketone bodies in subject(or in a biological sample from the subject) treated for a GLUT1deficiency, wherein an increase or decrease in the level of one or moreketone bodies compared to a predetermined standard level indicates or ispredictive of the treatment efficacy of the GLUT1 deficiency treatment.

Also included are methods for determining the treatment regimen fortreating a GLUT1 deficiency as described herein. Such methods includedetecting the level of one or more ketone bodies in a subject (or in abiological sample from the subject) treated for a GLUT1 deficiency anddetermining a treatment regimen based on an increase or decrease in thelevel of one or more ketone bodies.

Examples of ketone bodies include but are not limited tobeta-hydroxypentanoic acid (BHP), beta-ketopentanoic acid (BKP),3-hydroxypentanoate, and 3-ketopentanoate.

The levels of one or more Krebs cycle intermediates or their derivativesor one or more ketone bodies can be measured or determined using any ofa variety of methods known to those of skill in the art.

For example, in some embodiments, the one or more Krebs cycleintermediates and/or ketone bodies or their derivatives are measured ina biological sample (obtained) from a subject treated for a GLUT1deficiency. In some embodiments, the biological sample is selected fromblood, skin, hair follicles, saliva, oral mucous, vaginal mucous, sweat,tears, epithelial tissues, urine, semen, seminal fluid, seminal plasma,prostatic fluid, pre-ejaculatory fluid (Cowper's fluid), excreta,biopsy, ascites, cerebrospinal fluid, lymph, brain, and tissue extractsample or biopsy sample. In specific embodiments, C5 levels are measuredin the blood and/or urine.

In some embodiments, the one or more Krebs cycle intermediates and/orketone bodies or their derivatives are measured in the brain of thesubject. For example, in some embodiments, the one or more Krebs cycleintermediates and/or ketone bodies or their derivatives are measured bybrain imaging. In some embodiments, the brain imaging includes but isnot limited to computed axial tomography, diffuse optical imaging,event-related optical signal, magnetic resonance imaging, NMRspectroscopy, functional magnetic resonance imaging, magnetoencephalography, positron emission tomography, electroencephalography,near infrared spectroscopy, and single-photon emission computedtomography.

Additionally, the levels of the one or more Krebs cycle intermediatesand/or ketone bodies or their derivatives can be determined in order togenerate a composite of the level of the Krebs cycle intermediatesand/or ketone bodies. Certain methods include determining a compositelevel of a panel of selected Krebs cycle intermediates and/or ketonebodies. The composite can include but is not limited to any of the Krebscycle intermediates or ketone bodies described herein. In specificembodiments, C5 ketone body level information is included as part of thecomposite.

REFERENCES

-   1. Seidner G, Alvarez M G, Yeh J I, et al. GLUT-1 deficiency    syndrome caused by haploinsufficiency of the blood-brain barrier    hexose carrier. Nat Genet 1998; 18:188-91.-   2. Striano P, Weber Y G, Toliat M R, et al. GLUT1 mutations are a    rare cause of familial idiopathic generalized epilepsy. Neurology    2012; 78:557-62.-   3. Wang D, Pascual J M, Yang H, et al. Glut-1 deficiency syndrome:    clinical, genetic, and therapeutic aspects. Ann Neurol 2005;    57:111-8.-   4. Brockmann K. The expanding phenotype of GLUT1-deficiency    syndrome. Brain Dev 2009; 31:545-52.-   5. Schneider S A, Paisan-Ruiz C, Garcia-Gorostiaga I, et al. GLUT1    gene mutations cause sporadic paroxysmal exercise-induced    dyskinesias. Mov Disord 2009; 24:1684-8.-   6. Graham J M, Jr. GLUT1 deficiency syndrome as a cause of    encephalopathy that includes cognitive disability,    treatment-resistant infantile epilepsy and a complex movement    disorder. Eur J Med Genet 2011.-   7. Klepper J, Leiendecker B. GLUT1 deficiency syndrome—2007 update.    Dev Med Child Neurol 2007; 49:707-16.-   8. Freeman J M, Kossoff E H. Ketosis and the ketogenic diet, 2010:    advances in treating epilepsy and other disorders. Adv Pediatr 2010;    57:315-29.-   9. Brunengraber H, Roe C R. Anaplerotic molecules: current and    future. J Inherit Metab Dis 2006; 29:327-31.-   10. Roe C R, Mochel F. Anaplerotic diet therapy in inherited    metabolic disease: therapeutic potential. J Inherit Metab Dis 2006;    29:332-40.-   11. Roe C R, Sweetman L, Roe D S, David F, Brunengraber H. Treatment    of cardiomyopathy and rhabdomyolysis in long-chain fat oxidation    disorders using an anaplerotic odd-chain triglyceride. J Clin Invest    2002; 110:259-69.-   12. Mochel F, DeLonlay P, Touati G, et al. Pyruvate carboxylase    deficiency: clinical and biochemical response to anaplerotic diet    therapy. Mol Genet Metab 2005; 84:305-12.-   13. Roe C R, Yang B Z, Brunengraber H, Roe D S, Wallace M, Garritson    B K. Carnitine palmitoyltransferase II deficiency: successful    anaplerotic diet therapy. Neurology 2008; 71:260-4.-   14. Mochel F et al. Dietary anaplerotic therapy improves peripheral    tissue energy metabolism in patients with Huntington's disease. Eur    J Hum Genet 2010; 18:1057-60.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity ofunderstanding, it will be readily apparent to one of ordinary skill inthe art in light of the teachings of this invention that certain changesand modifications may be made thereto without departing from the spiritor scope of the appended claims. The following examples are provided byway of illustration only and not by way of limitation. Those of skill inthe art will readily recognize a variety of non-critical parameters thatcould be changed or modified to yield essentially similar results.

EXAMPLES Example 1

Subjects exhibiting GLUT1 deficiency and associated clinical symptomsare treated with triheptanoin. Subjects are administered triheptanoinwith each meal at a dosage sufficient to account for about 30-35% of thesubject's caloric intake with or without other anti-epileptic drugs. Thesubjects' seizure frequency is reduced and their neurologic and movementdisorder is improved due to the restoration of brain energy metabolismand net biosynthesis.

1. A method of treating a GLUT1 deficiency in a human subject in needthereof, comprising administering to the subject an odd-chain fatty acidsource.
 2. The method of claim 1, where the subject has adisease-associated mutation in at least one SLC2A1 gene.
 3. The methodof claim 2, where the subject has experienced one or more GLUT1deficiency-associated conditions selected from seizures, dystonicmovements, developmental delay, acquired microcephaly, spasticity,ataxia, and paroxysmal exertion-induced dyskinesia.
 4. The method ofclaim 1, where the subject has hypoglycorrhachia without hypoglycemia.5. The method of claim 4, where the hypoglycorrhachia is characterizedby one or more of cerebrospinal fluid (CSF) glucose of about or lessthan about 2.2 mmol/L, CSF lactate of about or less than about 1.3mmol/L, or a ratio of CSF/plasma glucose of about or less than about0.4.
 6. The method of claim 1, where the subject is diagnosed withdecreased 3-O-methyl-D-glucose uptake in erythrocytes.
 7. The method ofclaim 1, where the subject has cerebral fluoro-deoxy-glucose positronemission tomography (PET) findings characterized by diffusehypometabolism of the cerebral cortex and regional hypometabolism of thecerebellum and thalamus.
 8. The method of claim 1, where the odd-chainfatty acid source is administered as a unit dosage of about 2-150 grams.9. The method of claim 1, where the subject is an infant and theodd-chain fatty acid source is administered as a unit dosage of about1-6 grams/kg.
 10. The method of claim 1, where the subject is a youngchild, adolescent, or adult and the odd-chain fatty acid source isadministered as a unit dosage of about 0.5-4 grams/kg.
 11. The method ofclaim 1, where the odd-chain fatty acid source provides at least about30-35% of the total calories in the diet of the subject.
 12. The methodof claim 1, where the odd-chain fatty acid source is administered atabout 1 to about 10 grams/kg/24 hours, about 1 to about 5 grams/kg/24hours, or about 1 to about 2 grams/kg/24 hours.
 13. The method of claim1, where the odd-chain fatty acid source is administered three times aday, twice a day, or once per day.
 14. The method of claim 1, where theodd-chain fatty acid source is administered for one month, two months,six months, twelve months, or eighteen months.
 15. The method of claim1, where the odd-chain fatty acid source is administered in the absenceof a ketogenic diet.
 16. The method of claim 1, where the odd-chainfatty acid is administered as part of a ketogenic diet.
 17. The methodof claim 1, comprising oral administration of the odd-chain fatty acid.18. The method of claim 17, where the odd-chain fatty acid is formulatedwith food, optionally as an oil supplement or powder supplement.
 19. Themethod of claim 17, where the odd-chain fatty acid is formulated as anoil supplement.
 20. The method of claim 17, where the odd-chain fattyacid is formulated as a gel capsule.
 21. The method of claim 1, wherethe odd-chain fatty acid is administered in combination with ananti-seizure medication.
 22. The method of claim 1, where the odd-chainfatty acid source comprises triheptanoin or a derivative thereof. 23.The method of claim 22, where the triheptanoin is ultrapuretriheptanoin.
 24. The method of claim 1, where the administrationprovides a statistically significant therapeutic effect for thetreatment of a GLUT1 deficiency and optionally a GLUT1deficiency-associated disorder or condition.
 25. The method of claim 1,comprising detecting the level of one or more Krebs cycle intermediatesin the subject treated for a GLUT1 deficiency, and determining atreatment regimen based on an increase or decrease in the level of oneor more Krebs cycle intermediates.
 26. The method of claim 1, comprisingdetecting the level of one or more Krebs cycle intermediates orderivatives in the subject treated for a GLUT1 deficiency, wherein anincrease or decrease in the level of one or more Krebs cycleintermediates or derivatives compared to a predetermined standard levelis predictive of the treatment efficacy of the GLUT1 deficiencytreatment.
 27. The method of claim 1, comprising detecting the level ofone or more ketone bodies in the subject treated for a GLUT1 deficiencyand determining a treatment regimen based on an increase or decrease inthe level of one or more ketone bodies.
 28. The method of claim 1,comprising detecting the level of one or more ketone bodies in thesubject treated for a GLUT1 deficiency, wherein an increase or decreasein the level of one or more ketone bodies compared to a predeterminedstandard level is predictive of the treatment efficacy of the GLUT1deficiency treatment.
 29. The method of claim 27, where the ketonebodies are selected from 3-hydroxypentanoate and 3-ketopentanoate. 30.The method of claim 25, where the one or more Krebs cycle intermediatesor the one or more ketone bodies are measured in a biological samplefrom a subject treated for a GLUT1 deficiency.
 31. The method of claim30, where the biological sample is selected from blood, skin, hairfollicles, saliva, oral mucous, vaginal mucous, sweat, tears, epithelialtissues, urine, semen, seminal fluid, seminal plasma, prostatic fluid,pre-ejaculatory fluid (Cowper's fluid), excreta, biopsy, ascites,cerebrospinal fluid, lymph, brain, and tissue extract sample or biopsysample.
 32. The method of claim 25, where the one or more Krebs cycleintermediates or the one or more ketone bodies are measured by brainimaging.
 33. The method of claim 32, where the brain imaging is selectedfrom computed axial tomography, diffuse optical imaging, event-relatedoptical signal, magnetic resonance imaging, functional magneticresonance imaging, magneto encephalography, positron emissiontomography, and single-photon emission computed tomography.
 34. A methodof treating or preventing diseases of the brain affecting energymetabolism in a subject, comprising administering to the subject aneffective amount of triheptanoin, where the administration oftriheptanoin restores mitochondrial energy function and net biosynthesisthrough anaplerosis. 35-38. (canceled)